If agricultural land be left uncultivated, in a few years the jungle returns, and signs are not lacking that a similar danger is always lying in wait for the fields of thought, which, by the labour of three hundred years, have been cleared and brought into cultivation by men of science. The destruction of a very small percentage of the population would suffice to annihilate scientific knowledge, and lead us back to almost universal belief in magic, witchcraft and astrology.

E: Top five, top five, boys. Johannes Kepler, who we've spoken about many times on this show. Well, it says he published his Mysterium Cosmigraphicum, which, translated is Mystery of the Cosmos. Now, I looked this up a little bit further, and I have more references referencing that this was the actual date he made the discovery, or he had the epiphany, as it were, as he was teaching his class, rather than actually the work getting published. The work got published a year later. So I'm going with that he came up with the epiphany; the idea. And the idea is, well, I mean, Kepler said it best in his official title of this book, which is
Forerunner of the Cosmological Essays, Which Contain the Secret of the Universe; on the Marvelous Proportion of the Celestial Spheres, and on the True and Particular Causes of the Number, Magnitude, and Periodic Motions of the Heavens; Established By Means of the Five Regular Geometric Solids

S: Right.

J: I'm sorry, I missed that. Can you say that again?

E: Available on Kindle and other e-books, I'm sure.

S: What's cool is that at this point in his career, Kepler was essentially the equivalent of a crank. He had an idea that was little more than mental masturbation / pattern recognition, and then elaborated on it significantly. It was this beautiful elegant geometrical mathematical pattern pareidolia, but it had absolutely nothing to do with reality. Of course if he never got past that; if he never got past his beautiful idea, we wouldn't know his name today, or he would be a footnote somewhere, but he basically would have been a crank. But that's not what happened.

J: Well, when did Kepler's laws come out? Was it soon after this? I forget.

E: It was after he collaborated with Tycho Brahe.

J: Yeah, that was a fruitful collaboration.

R: (unintelligible)

E: And not long after Brahe died -- and this was about 25 years later -- Kepler's book, Epitome -- The Epitome of Copernican Astronomy in 1615, so 20 years later. And that's where his three laws of planetary motion were contained, in which he came to the mathematical proofs about how planets revolve around the sun in elipses, not in perfect circles or any other perfect geometry having to do with it. It was still a mystery though as to why planets orbit in elipses. And as Carl Sagan reminds us in his brilliant series Cosmos, these are not only the laws that our planet and our solar system obey, but it's universal. Everywhere in the universe, this occurs.

S: Well, he didn't know about gravity.

B: That's kind of a key thing to be missing.

S: That had to wait for Newton.

J: How could he not know about gravity though?

S: Well, you take it for granted, but he didn't —

J: Quantified, you know, mathematical gravitation

S: Yeah, but even conceptually, he didn't even know that all matter attracted all other matter to itself by some force.

B: Right, yeah, it's even worse (unintelligible) mathematics.

S: Yeah, they were thinking about it in ways that are bizarre to our modern concept of things. I don't know what the actual state of thinking was in Kepler's time, but if you go back to like Aristotle, they were thinking that oh, the universe things have a natural tendency to move toward the center of the universe, you know, which is the center of the Earth. Like they were thinking in those kind of terms. Not anything equivalent to what we think of as gravity.

J: Over the weekend, while we were celebrating Bob's birthday and the 4th of July -- Happy Birthday, Bob -- I was talking about gravity and I said "If there's anything magical out there, it's gravity". Like, think about it, we started trippin' out about how weird gravity is, I mean, we really don't understand it. As we all know gravity is -- what -- it's like a bowling ball on a big trampoline; it leaves like a dimple in space-time, whatever. What the Hell does that mean?

R: That's not even a good way to look at it, right? It's become far too pervasive, and it's apparently so over-simplified that it's giving people a false image of what gravity actually is. But, however, I have a better image to give people.

S: It's one of those things that's hard to say we know what it is or we don't know what it is. We know a lot about gravity. We have models of what it is mathematically, in terms of space-time, etc. I mean, that's the whole General Relativity thing. But why is it the way it is, that we don't know. There's a deeper level question there, that we have not penetrated yet. Probably, at the heart of that is quantum gravity, right there, which is a problem we have yet to solve. At least we know where to look, sort of. If we're gonna say what aspect of physics strikes us as magic, I definitely think that quantum mechanics has to get the prize there. Right?

B: Yeah, absolutely. But Jay's point is well taken, though. This "spooky action at a distance" type thing that applies to various things: gravity, magnetism. And there's also quantum mechanics, of course, entaglement, and all that stuff, but yeah.

S: Right. But aren't all forces "spooky action at a distance"? It's just that the gravity, the distance is really big. Right?

B: That's right.

R: Yeah.

S: Nuclear forces are just way short. They're short, but they're still acting at a distance.

J: Yeah, it's also a little too convenient, isn't it. It holds us to the Earth, I mean, really?

B: Anthropic Principle.

J: Oh, yeah.

B: It goes without saying.

S: That's right. If the universe weren't exactly the way it is now...

B: It would be different!

R: Three oddballs.

S: Speaking of which, Bob, tell us about astronomers' attempts to reclassify galaxies.

B: This was pretty interesting. I enjoyed doing research on this one. I love it when 80+ years of conventional wisdom gets defenestrated, don't you, Steve?

S: All the time, yeah.

B: I'm sorry. People just don't use that word enough, so there it is. So you'd think after 80 years, we'd have a decent idea of galaxy classification. It was over 80 years ago that Hubble really figured out what was going on with galaxies, and that galaxies even exist. But now scientists at the University of Oxford in New Jersey -- wait a second. No wait, this is the Oxford University that's in the UK. They've concluded that 66% of all eliptical galaxies are not elipticals at all, but they're called "naked spirals". So this is a major deal in terms of galaxy classification and the proverbial textbooks will definitely need to be revised on this one. I think I need to quickly go over some of the major galaxy classifications. Are you guys familiar, there's eliptical galaxies, and spiral galaxies, they're pretty much the main classification. You've got the irregular ones, but they're kind of a special case, and there's no real structure to those guys. So the eliptical and spiral are the most important. The elipticals are basically back to the ellipse, they've got this ellipsoidal shape to them. They're very smooth and featureless. And they're generally spherical or flat and most elliptical galaxies they're older, they have these low mass stars, there's not much star formation going on there. But the other major type is the spiral which everyone is familiar with. Everyone has seen thousands of pictures of these beautiful spiral galaxies that are disk shaped, they've got these dusty curving arms going around, they're very flat, rotating disk with a central bulge. Very beautiful. Now there's also another subclassification of spirals and these are the barred spirals. These are the ones, they've got this barred structure going through the core. They're actually very striking. I really like barred spirals and actually there's some good evidence to suggest that the Milky Way is actually a barred spiral.

S: Yup.

B: So that's kind of a quick overview of these major galaxy types. It turns out though that if you want to actually identify these galaxies, we've seen millions of them, it's actually kind of hard to classify them, because you can imagine these galaxies existing in three dimensional space, they can present themselves in any orientation to us, at any angle, so the different angles can really make it difficult to get a handle on exactly what the structure is, in order to classify it. So then, if you can imagine these older spirals, these really old spiral galaxies, if you see them face on, you really don't have a great idea that they're -- you don't know that you're seeing them face on. And actually some of these older guys, there's like very little dust in them, it's really hard to see the spirals. I think the spirals actually can kinda unwind and kinda diffuse themselves after a really long time. But at any rate, they're very hard to detect if they're even there. So they actually look like it's an elliptical galaxy. You're not sure: is this an elliptical galaxy, or is this a spiral galaxy, so it's really difficult. So the key way to distinguish these two then, is actually the rotation rate. Right? Because these ellipticals -- there's kind of like no net no real net rotation; there's no uniform direction to them like you have in these fast rotating spirals. So enter this new ATLAS 3D Survey. And this is exactly what this survey was designed to do: to actually figure out what was going on in some of these non-spiral galaxies. And the survey looked at about 260 of these non-spirals as they call them. And what it did was is that it overlaid this grid pattern over the galaxy, and it looked at the spectra -- the light signature -- of every section of that grid pattern, and then it looked at where's the red shift, where's the blue shift, 'cause if it's red shifted, you know it's moving away, if it's blue shifted you know it's kinda going towards you. My take on this is that this is very subtle becuase if you imagine, if you've got a spiral that's face on like a plate, looking right at you, the motion is really either counterclockwise or clockwise, right? There's really not gonna be a lot of motion that's going away or directly towards you, so even if the galaxy is at a bit of an angle there's not going to be that much motion, so... I talked to a few people about this, and they were like what took them so long to figure this out? I'm just guessing that some of these blue and red shifts were pretty subtle. And this ATLAS 3D Survey was pretty powerful. So when they looked at the results they were like wow! Two thirds of what we once thought were ellipticals are clearly spirals. They just don't have this dust and gas, and they call them these "naked spirals".

The other key aspect of this whole thing is the tuning fork diagram. Steve, Jay, have you guys heard of Edwin Hubble's Tuning Fork Diagram?

J: Sure.

B: Imagine the classic shape of a tuning fork where you've got the handle and you've got these two prongs coming out. Now, in the handle you've got the ellipticals, and then on one prong you've got the regular spirals, and then on the other prong you've got the barred spirals, and Edwin Hubble came up with this diagram 80 years ago. And his thinking was that the ellipticals evolved into the sprials. But since the ellipticals really don't have any real net rotation, there's no way to think of them actually becoming ellipticals, so his idea was wrong but the diagram itself actually is valid. And you could actually classify the type of spiral it is, or type of elliptical it is based on where it is on this tuning fork. So, but you've got a problem now, right? How do you reconcile this new information with this diagram that astronomers have used for eight decades? So what they're doing then now is they're calling this the ATLAS 3D "Comb". So they're adding another prong to the diagram. So then what you'd have was you'd have the handle, which is the ellipticals, the true elipticals, and then you'd have three prongs: the spirals, barred spirals and then you'd have the naked spirals as another kind of prong so they're calling this the ATLAS 3D Comb.

E: So we went from a tuning fork to some kind of salad fork.

B: Yeah, that was my problem, Evan. It's funny that you should say that because three prongs or three tines, to me, that's not a comb, you're right, that's a fork, that's like a salad fork or whatever. But they already had "fork" in the tuning fork, so they figured, ah, we'll just go with the comb idea, I guess. Right? I can deal with it.

E: Oh well.

S: Have you guys played with the Galaxy Zoo?

J: No

B: No, I haven't had a chance yet.

R: Yeah

E: I washed my hands when I was done.

S: It's interesting. What I didn't expect is that the pictures of the galaxies are not as good or high res as I pictured or as I was imagining they were going to be. I'm like oh yeah, I would love to classify galaxies and I was expecting to see pictures of beautiful spirals or whatever. But it's a lot of really grainy clumps. Galaxy Zoo is a way to play at classifying galaxies. So they give you images of galaxies from Hubble, and then they walk you through the features to look for to describe and classify the galaxies.

B: So they're taking advantage of human pattern recognition

S: Yes. And people can actually get pretty good. You can get good at classifying galaxies.

R: It's similar to the Fold It thing we mentioned last week or the week before.

S: Folding (unintelligible) yeah.

R: Yeah, you're taking science and giving it to the masses, both for them to learn more about your research, and also for the research to get done, which is pretty cool.

Item #1: A new study shows that it is possible to learn how to deliberately forget information. Item #2: Research suggests that pigeons are very adept at recognizing human faces. Item #3: Medical engineers report that they have successfully built and tested a functioning "robotic" small intestine that is capable of replacing a significant portion of the small intestine in an animal.

If agricultural land be left uncultivated, in a few years the jungle returns, and signs are not lacking that a similar danger is always lying in wait for the fields of thought, which, by the labour of three hundred years, have been cleared and brought into cultivation by men of science. The destruction of a very small percentage of the population would suffice to annihilate scientific knowledge, and lead us back to almost universal belief in magic, witchcraft and astrology.

Voiceover: The Skeptics' Guide to the Universe is produced by SGU productions, dedicated to promoting science and critical thinking. For more information on this and other episodes, please visit our website at www.theskepticsguide.org. You can also check out our other podcast the SGU 5x5 as well as find links to our blogs and the SGU forums. For questions, suggestions and other feedback please use the contact us form on the website or send an email to info@theskepticsguide.org. If you enjoyed this episode then please help us spread the word by leaving us a review on iTunes, Zune or your portal of choice.